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A light from Paschen series of hydrogen atom is able to eject photoelectrons from a metal. Then the work function of the metal is
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$1.1 \mathrm{eV}$
In Paschen series electron transmits from some higher state to $n=3$ state
So photons of paschen series have energies, ranging from
$E_{\min }=E_{n=4}-E_{n=3}$
$\begin{aligned} & =-0.85-(-1.5 \mathrm{l}) \\ & =0.66 \mathrm{eV}\end{aligned}$
to $E_{\max }=E_{n=\infty}-E_{n=3}$
$\begin{aligned} & =0-(-1.5 \mathrm{l}) \\ & =1.51 \mathrm{eV}\end{aligned}$
So, if a photon of paschen series able to emit a photoelectron from a metal, then work function $\phi_0$ of metal must be such that,
$\phi_0 \leq$ Photon energy
or $\phi_0 \leq 1.51 \mathrm{eV}$
Only matching option is options (d).
So photons of paschen series have energies, ranging from
$E_{\min }=E_{n=4}-E_{n=3}$
$\begin{aligned} & =-0.85-(-1.5 \mathrm{l}) \\ & =0.66 \mathrm{eV}\end{aligned}$
to $E_{\max }=E_{n=\infty}-E_{n=3}$
$\begin{aligned} & =0-(-1.5 \mathrm{l}) \\ & =1.51 \mathrm{eV}\end{aligned}$
So, if a photon of paschen series able to emit a photoelectron from a metal, then work function $\phi_0$ of metal must be such that,
$\phi_0 \leq$ Photon energy
or $\phi_0 \leq 1.51 \mathrm{eV}$
Only matching option is options (d).
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